Method and apparatus for performing a memory operation on a fixed length block of data on a memory disk

Abstract

An optical disk apparatus has an optical head for recording information on or reproducing information from an optical disk. The optical disk has a number of spiral or concentric tracks and a number of sectors formed along the circumferential direction of the disk. The sectors are divided into a plurality of sector blocks along the circumferential direction of the disk. Each sector block includes a different number of sectors which are continuous along the circumferential direction and which have a substantially constant linear length. A memory stores at least the speed data for maintaining a constant relative speed between the optical head and optical disk and is determined for each block group having a predetermined number of blocks. Speed data corresponding to the designated sector block is read out from the memory and is supplied to a velocity control circuit. A motor is driven to maintain a constant linear velocity between the optical head and the tracks of the optical disk.

What is claimed is: 
     
       1. An apparatus for performing memory operations on a memory disk having spiral tracks, which include memory storage areas designated as a plurality of numbered blocks as basic memory units comprising: means for rotating said memory disk;   recording/reproducing means for recording data on, and reproducing data from, said tracks of said memory disk;   means for dividing each track of said memory disk into a plurality of sectors in a radial direction, each track of said disk having a fixed, same number of sectors as each other track which define a position within each track;   memory means for storing a proper speed data for said memory disk as a function of groups of said blocks;   control means for assigning to each block a track and a number of sectors, which number of sectors is determined in correspondence with the position of the particular track assigned to a block so that a fixed amount of data may be stored in each block, and for reading out said speed data of said memory disk corresponding to a number of a predetermined block from said memory means;   drive control means for driving said rotating means in accordance with said speed data read out from memory means by said control means to keep a constant relative speed between said recording/reproducing means and each of the tracks of said memory disk; and   means for radially moving said recording/reproducing means to a track and sector corresponding to said predetermined block.   
     
     
       2. A disk apparatus according to claim 1, wherein said control means reads out data representing a same speed for blocks having a same number of sectors. 
     
     
       3. A disk apparatus according to claim 1, wherein said memory means stores a data table including a rotational speed of said disk determined for blocks having a same number of sectors, a number of sectors forming a block, and a start sector number as a first block of said plural blocks. 
     
     
       4. A disk apparatus according to claim 3, wherein said control means includes means for calculating a start track number and start sector number corresponding to the predtermined block from the data table of said memory means. 
     
     
       5. A disk apparatus according to claim 1, wherein said rotating means includes motor means for rotating said disk, and said drive control means comprises means for converting said speed data from said control means into motor rotating data and means for converting said motor rotating data into a motor drive pulse signal and for supplying the motor drive pulse signal to said motor. 
     
     
       6. A disk apparatus according to claim 1, wherein said disk is an optical disk and said recording/reproducing means includes an optical head having a semiconductor laser. 
     
     
       7. A disk apparatus according to claim 1, wherein said moving means includes a linear motor. 
     
     
       8. Apparatus as in claim 1 wherein each block has a capcity of 4k bytes. 
     
     
       9. An apparatus for performing a memory operation on a block of data on a disk, comprising: means for specifying a block of data to be read, and providing a block number signal indicative thereof;   head means for reading data from a specified area on said disk;   addressing means for addressing said disk as one of a plurality of spiral tracks, and as one of a plurality of sectors of a predetermined angular extent within said spiral track, and for locating said head means at said addressed sector and track;   memory means for storing a table including a correspondence between a range of said block number signals and (a) a track where said range begins, (b) a number of sectors occupied by each block to allow each block throughout said disk to have a same data storage capacity, and (c) a proper rotating speed for each block;   control means for reading said track, sector and speed information and for determining a specific sector, track and speed corresponding to said block number signal, and for commanding said addressing means to locate said head means at said specific sector and track; and   means for rotating said disk at said specific speed.   
     
     
       10. Apparatus as in claim 9 wherein said head means is also for writing data to a specific area, and further comprising means for specifying a write block indicative of a location where data is to be written.   
     
     
       11. Apparatus as in claim 10 wherein when said control means determines a specific sector, track and speed, the sector determined is at a next sector boundary beyond the last sector in which a previous data was written. 
     
     
       12. Apparatus for performing a memory operation on a block of data on a disk, comprising: means for specifiying a memory storage area where data is to be written, and producing a write block number signal indicative thereof;   head means for writing data to a specific area on said disk;   addressing means for addressing said disk as one of a plurality of spiral tracks, and one of a plurality of sectors within said spiral track, each said sector being of a predetermined angular extent, and for locating said head means at said sector and track addressed;   memory means for storing a table including a correspondence between a range of blocks number signals and: (a) a track number indicative of a beginning point of said range, (b) a sector number within said beginning track number indicative of said beginning point of said range, (c) a number of sectors which each block in said range occupies so that all blocks throughout the disk have a same memory storage capacity, and (d) a proper speed for said disk rotation within said range;   control means for reading said start track, start sector, sector numbers and speed information, and for determining a specific track, sector and speed indicative of said write block, and for commanding said addressing means to such location; and   means for rotating said disk at said specific speed.   
     
     
       13. An apparatus as in claim 12 wherein said head means is also for reading data from a specific area of said disk. 
     
     
       14. Apparatus as in claim 12 wherein said rotating means includes: register means for storing a signal indicative of a sum of said specific speed signal and an offset value; and   means for rotating at a speed proportional to said stored value.   
     
     
       15. Apparatus as in claim 12 wherein a block header with a block number is stored at a beginning of each block. 
     
     
       16. A method for performing a memory operation on a block of data on a memory disk, comprising the steps of: addressing all areas on the memory disk in terms of one of a plurality of spiral tracks thereon, and one of a plurality of sectors within the spiral track, each sector being a predetermined angular extent of a spiral track;   storing in a memory a correspondence between block numbers and sectors, tracks, and speed to allow all memory blocks to have a same storage capacity;   determining a memory block to be addressed;   reading a sector, track, and speed from said memory corresponding to said addressed block;   calculating a start address and sector extent sector for said addressed block;   addressing said addressed block; and   rotating said memory disk at said speed read in said reading step.